The liquid crystal display device is a display device that is used for a notebook computer, a personal computer, a smart phone, a TV and the like, and its characteristics are also improved every year according to expansion of demand for the liquid crystal display device.
A liquid crystal panel of a liquid crystal display device as a non-light emitting element structurally requires a backlight unit. The backlight unit includes a light source and a plurality of optical sheets. The optical sheets diffuse or condense the incident light to supply uniform light to the liquid crystal panel.
However, because each of a prism sheet and a diffusion sheet used in a general backlight unit is separately manufactured and joined at the backlight assembling process, there is a problem in which the manufacturing of the backlight unit becomes complicated and its thickness increases.